This massive private terrace at 350 West Broadway also happens to come with a three-bedroom, 4½-bath, 3,521-square-foot condo. The full-floor, $10.35M unit in a glassy Aby Rosen-developed building includes 11-foot ceilings, marble baths and private elevator access. Contact: Corcoran Sunshine, 212-941-0350Lorenzo Ciniglio/Freelance

It was a rough winter for Conan O’Brien, but things are a lot sunnier now. After collecting $32 million in his NBC exit deal, he got a new late show on TBS. His comedy tour has been a sold-out smash. And, oh yeah, he just sold his plush duplex overlooking Central Park.

“Conan O’Brien’s apartment that recently sold had a quirky layout,” says Dolly Lenz, vice chairman of Prudential Douglas Elliman, “But it was the big terrace — the southeast-facing terrace — that sold it.”

That terrace, one of the apartment’s three private terraces, helped sell the apartment at the Majestic co-op building on Central Park West for close to its $29.5 million asking price.

Yes, when it comes to marketing the most high-end real estate in the city, outdoor space can make all the difference.

Lenz recently brokered a deal for an apartment on Central Park West that boasted 4,000 square feet of outdoor space. It sold almost the moment it went on the market for its full $13.9 million asking price. “They bought the interior for the exterior,” says Lenz. “It needed everything — it hasn’t been touched since 1964 — but it was pretty special because of the outdoor space.”

“Any time we are advising sellers who have a terrace, we tell them that spring is ideal,” says Diane Ramirez, president of Halstead Property, which is marketing a 4,400-square-foot Upper East Side duplex penthouse co-op with 5,000 square feet of terrace and an indoor pool for $5.5 million. “In fact, we tell people [who have outdoor space] towards the later winter to wait” and put the property on the market in the spring.

It’s an extremely sensible position, given that private outdoor space is a hot commodity — especially if you want it in a full-service building.

Francois Jeulin, for example, and his broker Cyrine Joaristi of the Real Estate Group of New York, have been searching for a luxury condo with significant outdoor space since April. They saw a 1,700-square-foot two-bedroom loft in TriBeCa with an additional 1,850-square-foot terrace for $2.55 million.

“There were a lot of options [for the terrace],” says Joaristi. “You could cover part of it, you could put in a Jacuzzi; there was a sunroom that [Jeulin] wanted to expand.”

Unfortunately, Jeulin didn’t act quickly enough — as he was getting ready to make an offer, another buyer snatched it up. He’s still on the lookout.

In recent years, developers have spent more time focusing on private outdoor space.

“Developers want to maximize all their assets,” says Brown Harris Stevens broker Wendy Maitland, who is marketing a $12.95 million townhouse on Centre Street that boasts a Tuscan garden and its own domed basketball court on the roof.

“Sometimes you have three or four floors of penthouses” in new buildings, Ramirez says. Why? It allows the developer to add more private terraces.

And while outdoor space is often priced at about 25 percent of the price-per-square-foot of interior space, the right terrace or roof deck can command a huge premium.

“In this hectic city, having a place to go out and have a cup of coffee on, or a place to take your dog, is the extra little special bit,” Ramirez says. “It’s just a jewel factor.”